THe ZM-2, 4Sqrp, SLT, and L-tuner all work.
Personally the 4sqrp, L-tuner, SLT, and Elecraft T1 are in use here for power up to 10W
and do the job for multiple QRP radios. For higher power I have a L-tuner I built that
easily takes 100W. Those only get used for the inverted L and the 160M Inverted V
as all my other antennas are 50 ohm resonant as that saves losses though a tuner
By far the best antenna is a matched one. Second best is any needing a tuner.